The present invention relates generally to electromagnetic railguns, and more specifically to a novel railgun muzzle arc suppressor.
Railguns are being considered as a primary component of a space based ballistic missile defense system. Additionally, smaller railguns have been considered for use in ground support. One of the primary requirements for a successful railgun is that it be able to fire repeatedly at a very rapid rate.
Railguns operate by using a very large electric current to create a very strong magnetic field. The interaction of the electric current and the magnetic field creates a force called a Lorentz force. The Lorentz force can propel an electrically conductive projectile between a pair of electrically conductive rails. The projectile can be accelerated at several 100,000's of g's and can reach muzzle velocities of several kilometers per second. As the projectile leaves the muzzle end of the railgun, thus opening the rail-projectile-rail circuit, the energy built-up in the magnetic field surrounding the rails is sufficient to cause arcing from the rail ends to the projectile. This arcing causes erosion and thermal damage to both the projectile and to the muzzle ends of the rails. The desired rapid and repetitive operation is prevented by the cummulative muzzle damage and wear.
Three general solutions have been proposed to reduce or eliminate the muzzle arcing. The first solution ceases adding energy to the railgun system well before the projectile leaves the rails, so that the built-up system energy is used to further accelerate the projectile along the rails until the energy falls below the point at which arcing will occur. The second solution provides additional railgun circuitry to electrically recover the excess energy to be reused in firing successive projectiles. The third solution to the muzzle arcing problem dissipates the excess magnetic energy by converting it to heat energy through a resistance. The first solution suffers primarily from requiring railgun lengths that are too long. The second solution is conceptially appealing, but a completely successful design using this approach has not appeared. U.S. Pat. No. 4,572,964 to Honig provides a brief discussion of the problems of the first solution and an example of a proposed apparatus using the second solution.
The third solution may present the simplest path to a successful rapid fire railgun. However, presently proposed apparatus implementing the third solution will only suppress, but not eliminate, arcing. Examples of those apparatus may be found in U.S. Pat. Nos. 4,423,662 to McAllister, and 4,437,383 to Deis et al. Deis et al also shows cooling of the resistive elements. Because energy dissipation by resistance converts the energy into heat, it is important that adequate cooling be provided to remove the heat at a fast enough rate to allow rapid refiring. Deis et al fails to disclose any teaching of how sufficient and rapid cooling may be accomplished.
It is, therefore, a principal object of the present invention to eliminate destructive muzzle arcing in railguns by dissipating excess railgun energy through a resistance.
It is another object of the present invention to provide a cooling system for the resistance that removes the converted heat energy from the resistive fast enough to permit rapid repetitive firing.
It is a further object of the present invention to provide a resistance that is conformable to the shape of the railgun rails to increase energy dissipation efficiency.
It is yet another object of the present invention to integrate the cooling system with the resistance to increase cooling efficiency.
A feature of the present invention is that it eliminates muzzle flash and reduces the signature of the railgun system.
Another feature of the present invention is that it eliminates the adding of excessive charged particles to the environment.
An advantage of the present invention is that nearly no railgun system energy leaks through the resistance during active acceleration of the projectile.
Another advantage of the present invention is that it provides an adaptable structure for both energy dissipation and reclamation of excess railgun magnetic energy.
Yet another advantage of the present invention is that its very large energy absorption ability permits a reasonably sized dissipating and cooling structure.